As is well known, it is an established application of carbon-functional organosilane compounds of various types that the silane compound is used as a so-called silane coupling agent which enhances compatibility and adhesion between different materials such as an inorganic and organic materials to be combined. A class of the carbon-functional organosilane compounds having an activity as a silane coupling agent includes those having an amino group or N-substituted amino group bonded to the silicon atom of the silane compound through a divalent hydrocarbon group. One of typical amino group-containing silane compounds is 3-aminopropyl trimethoxy silane and this compound is widely used as a silane coupling agent for the surface treatment of plastic articles and synthetic fibers and for adhesion promotion of sealants and adhesives. Though quite effective in respect of the activity as a silane coupling agent, these amino group-containing silane compounds have various disadvantages and problems. For example, conventional amino-functional silane coupling agents in general have relatively low water-resistance so that, when such a silane coupling agent is used as an adhesion promotor in a silicone rubber composition, the adhesive bonding strength between the cured silicone rubber and the substrate surface on which the composition has been cured is decreased in the lapse of time by immersion in water. When the amino-functional silane coupling agent is used as a surface-treatment agent for silicon dioxide fillers and the like to be compounded in a sealant such as those based on an epoxy resin used in electric and electronic parts, the moistureproofing effect of the sealant is sometimes not high enough.
Accordingly, it is eagerly desired to develop an amino group-containing organosilane compound having excellent activity as a silane coupling agent but free from the disadvantages and problems in the conventional amino group-containing silane compounds mentioned above. The inventors have conducted extensive investigations to discover or uncover a silane compound to meet the above mentioned requirements including synthetic preparation of various amino group-containing organosilane compounds and testing thereof as a silane coupling agent. The organosilane compounds synthesized in the course of this synthetic work included several novel silane compounds not known in the prior art nor described in any literature, of which the fluorocarbon group-containing alkoxy silane compounds proposed here were found to be particularly useful as a silane coupling agent.